unit 4 - digestive system Flashcards
what does the digestive system do?
- helps to break down food and absorb nutrients into our blood
- a long tube from mouth to the anus with specialised regions to break down food so it can pass into blood and go to cells
bile and pancreatic juices
- filled with digestive enzymes
- specialised proteins that chemically change the nutrients from food into forms that can be absorbed into blood
- this is known as chemical digestion
why does digestion occur
as we need to break down food so it can be absorbed into plasma
what are the two types of digestion
mechanical digestion
chemical digestion
what happens during mechanical digestion
1- chew food to make it small enough to swallow
2- churn food in stomach to make chyme
chyme is in a form that provides easier access to nutrients for the digestive system
what happens during chemical digestion
- protein, carbs and fats are too big to go throguh wall of gut
- digestive enzyme breaks down bonds so they can become smaller molecules
- occur in mouth, stomach and first section of small intestine
why are there so many enzymes in chemical digestion
- different enzymes are needed for each food group
- different enzymes work in alkaline or acidic environments
absorption in villi
- villi contain capillaries and a lacteal (lymph system)
- they increase the surface area of the illum so that as many as possible nutrients are absorbed
how does absorption take place
- most nutrients enter through diffusion into capillaries and then to the liver
- but, fat is less absorbable and enters via the lacteal
- links to bloodstream via left subclavian vein along with vitamins
- delivers to the liver
function of salivary glands
- moisten food to make it easier to swallow
- contains enzymes that help start the breakdown of food
function of Bugal Cavity (mouth)
- ingestion : break down food
- use tongue, teeth, jaws
function of small intestine
- aid digestion and breakdown of foods
- chyme passes here and mixes with bile and pancreatic juice
- food remains here for 4 hours
function of rectum
- stores faeces
- remains of dried food
function of liver
- make bile
function of gallbladder
- store bile
function of pancreas
- produce pancreatic juices
function of anus
- excretes faeces at an appropriate time
role of the liver
- caries out 500 functions in the body
- sorts, stores and distributes nutrients (assimilation)
- extra glucose is converted into glycogen, ready to be used as energy
- toxins like alcohol are broken down by liver
role of pancreas
- produce pancreatic juices containing enzymes that are put into small intestine
- enzymes in juice break down fats, carbs and proteins (chemical digestion)
- produces hormone insulin
pancreatic juices
- released from pancreas into small intestine
- neutralise the chyme because they are alkaline
- contain chemicals called enzymes which break down food into carbs, fats and proteins
disorders of the digestive system
- gallstones
- irritable bowel syndrome (IBS)
- coeliac disease
diagnosis of digestive system disorders
- food and symptom diary
- ultrasound
- endoscopy
- biopsy
food and symptom diary
- keep track of food eaten and any symptoms for a given period of time
- dairy can be assessed by a doctor to identify triggers and frequency of symptoms
ultrasound for digestive system
- images with sound waves which make images
- used to help diagnose pain or distention and evaluate the liver, gallbladder or pancreas
- it’s safe, non invasive, and doesn’t use ionizing radiation
endoscopy
- involves inserting a tube that high a light and video camera
- inserted into either end of digestive system
- images are then related onto screens so doctors can see live images
biopsy
- sample of tissues removed from body for examination under microscope
- look at very small structures and identify changes
treatments for disorders of digestive system
- lifestyle changes (reduce cholesterol, gluten free, exercise, reduce stress, alcohol)
- lithotripsy (gallstones) - high frequency sound waves to break gallstones into small particles so the body naturally passes them
bile
- produced in liver
- stored in gall bladder
- enter small intestine via bile duct
- it emulsifies fat and neutralises stomach acid and salts in bile to break down fats into tiny globules to form an emulsion
gallstones
- form in gallbladder
- happen because of high cholesterol in bile causing crystals to form and grow in size
symptoms of gallstones
- pain
- discomfort
- sweating
- nausea
causes of gallstones
- females have higher risk
- overweight
- hereditary
- fatty meals might trigger pain
irritable bowel syndrome
- muscles that line digestive system have normal rhythm affected
- mainly in the colon
symptoms of irritable bowel syndrome
- diarrhoea, constipation, abdominal pain, bloated feeling, indigestion, flatulence
causes of irritable bowel syndrome
- not fully understood
- alcohol
- fizzy drinks
- caffeine
- chocolate
- fried food
- processed foods
- stress
what is coeliac disease
- autoimmune disease meaning immune system mistakes our own tissue as being harmful and destroys them
symptoms of coeliac disease
- abdominal pain
- bloating feeling
- flatulence
- weight loss
- diarrhea
- can lead to anemia and osteoporosis
causes of coeliac disease
- family link
- infection in gut during childhood might trigger it later in life
